Upper vent of a multi-chamber blowoff valve



FIG. 1 is a perspective view of an upper vent of a multi-chamber blowoff valve showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a back elevation view thereof; and,

FIG. 5 is a bottom plan view thereof.

The features shown in broken lines depict environmental structure only and form no part of the claimed design. 

CLAIM The ornamental design for an upper vent of a multi-chamber blowoff valve, as shown and described. 